A guide to the deep-water sponges of - NMFS Scientific Publications ...

122 Professional Paper NMFS 12
102. Halichondria sp.
Description. This sponge is extremely polymorphic;
reported growth forms include encrusting, massivelobate,
tubular, lobate, and vase-shaped. Oscula may
be flush with the surface, slightly elevated, or on larger
cone-shaped elevations. Consistency is only slightly
elastic but easily fragmented. Size is to at least 30 cm ×
30 cm. Color in life ranges from brown, grey, orange,
green, yellow, to creamy white.
Skeletal structure. Ectosomal spicules are tangentially
arranged. Choanosomal arrangement of spicules
is mostly confused but in places may be a unispicular
reticulation or meshes of polyspicular tracts. Spicules
are oxeas (220–335 × 15–24 µm).
Zoogeographic distribution. Locally abundant. In
Alaska – Aleutian Islands, Bering Sea (Pribilof Canyon),
and eastern Gulf of Alaska. Elsewhere – North Pacific
Ocean.
Habitat. In Alaska – attached to hard substrate. Depths
between 155 and 208 m (Aleutian Islands); depths between
71 and 255 m (eastern Gulf of Alaska); Bering
Sea (Pribilof Canyon) – locally abundant; attached to
bedrock, cobbles, pebbles, and encrusting the gorgonian
coral Plumarella echinata at depths between 208 and
309 m. Elsewhere – no information available.
Remarks. This species might represent an undescribed
species. The Alaskan specimens are similar to
Halichondria panicea (Pallas, 1766) that is common to
the North Atlantic Ocean and was recently introduced
to San Francisco Bay. Alaskan specimens have a slightly
different external appearance and the spicules are
shorter and more robust than those of H. panicea. There
are ongoing discussions about whether there are several
sibling species or whether the Atlantic and Pacific
Ocean populations are conspecific (Erpenbeck and Van
Soest, 2002). Eggs and hatching larvae similar to those
of the snailfish (Careproctus sp.) were found in flabellate
forms of this species in Pribilof Canyon, Bering Sea
(Busby 4 ). This species is preyed upon by the sea stars
Hippasteria spp., Pteraster tesselatus, Ceramaster patagonicus,
and possibly Henricia longispina.
Photos. 1) Specimen collected at a depth of 175 m
in the central Aleutian Islands. Grid marks are 1 cm 2 .
2) Same specimen as in photo 1 in situ. The specimen
was detached and lying on the seafloor in an area that
had been trawled. 3) A fragment of a specimen collected
at 152 m in the eastern Gulf of Alaska. Grid marks
are 1 cm 2 . 4) Same specimen as in photo 3 (lower right)
in situ. Crinoids (Florometra serratissima) use the sponge
as an elevated perch. 5) Specimen collected at a depth
of 310 m in Pribilof Canyon, Bering Sea. This specimen
has completely encrusted the gorgonian Plumarella
echinata (tips exposed at right). Grid marks are 1 cm 2 .
6) Same specimen as in photo 5 (indicated by the white
arrow) in situ. 7) Specimen collected at a depth of 155
m in the central Aleutian Islands. Grid marks are 1 cm 2 .